mega ultra simple photoblog script needed

I’m trying to put together a project I’ve been working on for a while. What I want is a simple php script that I can put in a folder with a group of images. The script should display only the two images with the highest number in the name. (For example, 23_image.jpg, 24_image.jpg.) I want to be able to simply upload new images into the folder and have the script display only the two most recent. Also perhaps the ability to browse back and forth through the images in the folder. A real bonus would be the ability to display a list of links that would add a number each time a new photo was uploaded. Would be nice to be able to customize layout with CSS. I’m a php newbie, so hopefully this script exists already. Or maybe another approach entirely would be best.